<!--
 * @Description: 盒子模型
 * @Author: rendc
 * @Date: 2024-11-05 14:40:52
 * @LastEditors: rendc
 * @LastEditTime: 2024-11-05 14:58:00
-->
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>盒子模型</title>
  <style>
    #app{
      /* 默认状态：内容盒子 */
      /* box-sizing: content-box; */
      /* 修改为边框盒子 */
      box-sizing: border-box;
      width : 100px;
      height:100px;
      border: 1px solid red;
      padding: 10px;
      padding-top: 20px;
      padding-left: 30px;
      margin: 10px;
      margin-bottom: 40px;
      margin-right: 80px;
      margin: 10px 20px 30px 40px;
    }
  </style>
</head>
<body>
  <div id="app">
    盒子模型
  </div>
</body>
</html>